// Note: add_action must follow'woocommerce_account_{your-endpoint-slug}_endpoint' format Use a Shortcode for ContentYou could even use the core WordPress function do_shortcode and render a pre-defined shortcode in your custom tab. In order to do that, just replace the part defining the content with something like this:  

If you want to limit the ACF field character output. you can use below code. 1) Make sure to use get_field instead of the_field to get the value. 2) I would recommend using the built in WP function wp_trim_words